AO Smith — Geyser malfunctioning unit XPRESS-025

Geyser malfunctioning unit XPRESS-025 since purchase.
Thermostat had to replaced after each heat cycle for 3-4 times within the warranty period.

Last time it stopped working and warranty finished. I had told the case history that please replace the unit as it is not functioning properly since purchase.
However, I was charged for spares and visit.

Again, after a heat cycle it has stopped working next day after the replacement.
Complaint raised for 15 days. They simply say they are working on it.
I want replacement or refund of the money of the unit purchased +spent on repair.

Wastage of time, money and great inconvenience.